US20070014529A1 - Improved Coupling of Communications Signals to a Power Line - Google Patents

Abstract

In one embodiment, a device for coupling communications signals onto a medium-voltage power line includes a first connector, a second connector and one or more components. The first connector is adapted to couple to a low-voltage communications line. The second connector is adapted to couple to a surge arrester. The one or more components are operable to substantially match the impedances between the surge arrester and the low-voltage communications line.

Description

RELATED APPLICATION
• This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application Ser. No. 60/700,038 filed Jul. 15, 2005.
TECHNICAL FIELD
• This invention relates generally to communications networks and in particular to a system and method for improved coupling of communications signals to a power line.
BACKGROUND
• Power systems utilize a variety of electrical devices and connectors to deliver electricity from a power station or generator to customers. Some power systems utilize a three-tiered approach that utilizes high-voltage power lines with voltages in the range from approximately 60 kV to 100 kV, medium-voltage power lines with voltages in the range from approximately 4 kV to 60 kV, and low-voltage power lines with voltages in the range from approximately 90V to 600V.
• In these three-tiered power systems, high-voltage power lines typically connect a power station or generator to a substation. The substation serves a particular area such as a neighborhood and includes a transformer to step-down the voltage from high voltage to medium voltage. Typically, multiple sets of medium-voltage power lines connect the substation to local distribution transformers. The distribution transformers typically serve the customers in close proximity to the distribution transformer and step-down the voltage from medium voltage to low voltage for use by the customers.
• The power lines used to deliver electricity to customers have also been used to transmit and receive communications signals. For example, power lines have been used by utility companies to transmit and receive communications signals to monitor equipment and to read meters. Power lines have also been used to provide broadband communications for customers. Various techniques have been developed to couple broadband communications signals to medium-voltage power lines. These broadband communications signals typically occupy frequencies in the 2-50 MHz region. One approach to coupling communications signals to these medium-voltage power lines is to use the intrinsic capacitance of metal oxide varistor (MOV) lightning arresters to couple a portion of the communications radio frequency signals onto medium-voltage power lines. Most MOV lightning arresters have a special device attached to the bottom of the arrester assembly to explosively disconnect the grounding wire in case of a current fault. This device usually consists of a grading resistor in parallel with an air-gap and small gunpowder charge.
SUMMARY OF THE INVENTION
• In one embodiment, a device for coupling communications signals onto a medium-voltage power line includes a first connector, a second connector and one or more components. The first connector is adapted to couple to a low-voltage communications line. The second connector is adapted to couple to a surge arrester. The one or more components are operable to substantially match the impedances between the surge arrester and the low-voltage communications line.
• Particular embodiments of the present invention may provide one or more technical advantages. For example, certain embodiments of the present invention may provide improved transmission and throughput of communications signals. As another example, in certain embodiments, the size and placement of the coupling device may provide for relatively quick and simple installation with little or no modifications to existing equipment. In these embodiments, such relatively quick and simple installation may allow for rapid deployment of communications coverage and/or rapid repair in the event of a localized surge or lightning strike. Certain embodiments of the present invention may provide one or more of these technical advantages at a relatively low cost.
• Certain embodiments of the present invention may improve the coupling efficiency for systems utilizing MOV lightning arresters with explosive disconnect devices. These disconnect devices have been shown to limit the efficiency of communications signal transmission over medium-voltage power lines. The arrester disconnect device can cause the frequency response of a communications signal coupler to roll-off prematurely and limit or prevent the use of lower frequencies between communications devices. By bypassing this disconnect device at radio frequencies, certain embodiments of the present invention may reduce the series impedance contribution of the disconnect device and thereby reduce or eliminate this performance problem.
• In addition, certain embodiments may provide one or more other technical advantages some, none, or all of which may be readily apparent to those skilled in the art from the figures, descriptions, and claims included herein.
BRIEF DESCRIPTION OF THE DRAWINGS
• To provide a more complete understanding of the present invention and the features and advantages thereof, reference is made to the following description taken in conjunction with the accompanying drawings, in which:
• FIG. 1 illustrates a portion of an example power-line communications system, according to a particular embodiment;
• FIG. 2 illustrates an example regenerator unit included in certain embodiments of a power-line communications system;
• FIG. 3 illustrates an example customer-access unit included in certain embodiments of a power-line communications system;
• FIG. 4 illustrates an example regenerator/customer-access unit included in certain embodiments of a power-line communications system;
• FIG. 5 illustrates a portion of an example power-line communications system including an example surge arrester and an example coupler, according to a particular embodiment;
• FIG. 6 illustrates a circuit diagram of a portion of an example power-line communications system, according to a particular embodiment;
• FIG. 7 illustrates a component diagram of an example coupler, according to a particular embodiment;
• FIG. 8 illustrates a portion of an example power-line communications system including an example surge arrester, an example disconnect device, an example parallel bypass including an example bypass capacitor, and an example coupler, according to a particular embodiment;
• FIG. 9 illustrates a circuit diagram of an example medium-voltage power line disconnect device;
• FIG. 10 illustrates a circuit diagram of an example medium-voltage power line disconnect device with an example parallel bypass including an example bypass capacitor, according to a particular embodiment;
• FIG. 11 illustrates a circuit diagram of a portion of an example power-line communications system, including an example disconnect device and an example parallel bypass including an example bypass capacitor, according to a particular embodiment;
• FIG. 12 illustrates a component diagram of a coupler, including a bypass capacitor, according to a particular embodiment;
• FIG. 13 illustrates a component diagram of a coupler, including a bypass capacitor and impedance matching components, according to a particular embodiment;
• FIG. 14 illustrates a portion of an example power-line communications system including an example surge arrester, an example disconnect device, an example parallel bypass, and an example coupler, according to a particular embodiment; and
• FIG. 15 illustrates a circuit diagram of a portion of an example power-line communications system, including an example disconnect device and an example parallel bypass, according to a particular embodiment.
DESCRIPTION OF EXAMPLE EMBODIMENTS
• It should be understood at the outset that although example embodiments of the invention are illustrated below, the present invention may be implemented using any number of techniques, whether currently known or not. The present invention should in no way be limited to the illustrated embodiments, drawings, and techniques. Additionally, the drawings are not necessarily drawn to scale.
• FIG. 1 illustrates a portion of an example power-line communications system, indicated generally at10, utilizing medium-voltage power lines to carry communications signals. In certain embodiments, power-line communications system10 may function to provide one or more customers with access to a wide area network (WAN). For example, power-line communications system10 may function to provide one or more customers with access to data services, video services, voice-over-Internet-Protocol (VoIP), or plain-old-telephone service (POTS). As another example, the communications signals may represent upstream and/or downstream traffic at transmission rates of at least 200 kpbs. In a particular example, power-line communications system10 may function to provide one or more customers with access to the Internet. In certain embodiments, power-line communications system10 may include medium-voltage phase line12,neutral line14,surge arrester16, andcommunications device18.
• Medium-voltage phase line12 represents a transmission power line operable to conduct medium-voltage electricity. In certain embodiments, medium-voltage phase line12 may be an overhead transmission line. In particular embodiments, medium-voltage phase line12 may conduct an alternating current (AC) of electricity between approximately 4 and 60 kilovolts. In embodiments of power-line communications system10 includingneutral line14,neutral line14 may represent a power line of the same or similar structure and capability as medium-voltage phase line12.
• Communications device18 may broadly represent a device for receiving and/or transmitting communications signals. For example, in certain embodiments,communications device18 may represent a regenerator unit, a customer-access unit, or a combination regenerator/customer-access unit. In certain embodiments,communications device18 couples to medium-voltage phase line12, as described below, and may also couple toneutral line14 and/or a ground connection through the use ofconductor28.Conductor28 may represent any appropriate wire or cable, such as, for example, a standard #4 or #6 AWG solid copper wire. Example embodiments ofcommunications device18 are describe below in relation toFIGS. 2-4.
• Surge arrester16 may represent a device for electrically coupling medium-voltage phase line12 toneutral line14 and/or a ground connection in the event of an over-voltage condition. In certain embodiments,surge arrester16 may represent a metal oxide varistor (MOV) lightning arrester. For example,surge arrester16 may represent an Ohio Brass HD Arrester, 18 KV class, or any other appropriate lightning arrester for use with medium-voltage phase line12.
• In operation,communications system10 may enable one or more end-users to transmit and/or receive communications signals using medium-voltage phase lines12. In certain embodiments, communications signals are coupled to medium-voltage phase line12 and carried to and/or from one ormore communications devices18. In certain embodiments, the communications signals are transmitted from medium-voltage phase line12 tocommunications device18 using the intrinsic capacitance of a metal oxide varistor (MOV) arrester. In certain embodiments,communications system10 may enable multiple end-users to transmit and/or receive broadband communications signals. For example, the broadband communications signals may represent upstream and/or downstream traffic at transmission rates of at least 200 Kbps.
• Although, certain aspects and functions of the present invention are described in terms of receiving and/or transmitting communications signals, in certain embodiments, these functions may be reversed, as may be appropriate, without departing from the spirit and scope of the present invention.
• FIG. 2 illustrates anexample regenerator unit18aincluded in certain embodiments of power-line communications system10. In the example shown,regenerator unit18aincludeshousing100, twomodems102,switch104, andwireless access point106.
• Housing100 operates to create an enclosed area containing the elements ofregenerator unit18a. In certain embodiments,housing100 may operate to protect the elements ofregenerator unit18aand to simplify the installation ofregenerator unit18aby keeping the elements ofregenerator unit18atogether with the appropriate internal connections. In certain embodiments,housing100 may also provide structural support for the elements ofregenerator unit18aand may provide electrical insulation between certain elements ofregenerator unit18a. In certain embodiments,housing100 may represent a weather proof, sealed container to enclose moisture sensitive elements ofregenerator unit18a. For example,housing100 may include a hinged aluminum case with one or more rubber seals and threaded closures. In a particular embodiment,housing100 may have dimensions of less than 12 inches in height, width, and depth. For example,housing100 may be a weatherproof Scientific-Atlanta CATV Line Extender Housing. However, any appropriate container may be used to contain the elements ofregenerator unit18aand/or the elements ofregenerator unit18amay be contained individually or in other combinations.
• Modems102 are electrically coupled to medium-voltage power line12. In operation, modems102 demodulate communications signals received from medium-voltage power line12 and/or modulate communications signals for transmission on medium-voltage power line12. Thus modems102 represent any appropriate hardware and/or controlling logic for modulating and/or demodulating communications signals. In certain embodiments,modems102 receive and transmit RF signals. For example, modems102 may represent a HomePlug Powerline Alliance (HPA) compliant modem or a Universal Powerline Association (UPA) compliant modem. In certain embodiments,modems102 may transmit and receive communications signals through a coaxial connection using an F-connector. In a particular embodiment, modems102 may represent NetGear modems. Although, in certain embodiments,multiple modems102 may be the same, this is not necessary.
• Switch104 may couple tomodems102 andwireless access point106. In operation, switch104 operates to receive and transmit digital communications signals among the elements ofregenerator unit18a. Thus, switch104 may represent any appropriate hardware and/or controlling logic for directing the flow of digital communications signals among multiple elements ofregenerator unit18a. For example, in certain embodiments, switch104 may be a router, a hub, an Ethernet switch, or a network processor. In certain embodiments, switch104 may have an IP address that is unique within power-line communications network10.
• In embodiments ofregenerator unit18aincludingwireless access point106,wireless access point106 operates to transmit and/or receive wireless communications signals. Thuswireless access point106 represents any appropriate hardware and/or controlling logic for transmitting and/or receiving wireless communications signals. In certain embodiments,wireless access point106 may transmit and/or receive wireless communications signals using an IEEE 802.11 standard protocol. In a particular embodiment, wireless access point may be a D-Link wireless access point coupled to switch104 through the use of 10/100 base-T connectors.
• In operation,regenerator unit18areceives communications signals from medium-voltage power line12, demodulates the received communications signals, re-modulates at least a portion of the received communications signals, and transmits the re-modulated communications signals to medium-voltage power line12. Thus, in certain embodiments,regenerator unit18aoperates to allow communications signals to travel greater distances along medium-voltage power line12 by preventing excess attenuation. Accordingly,regenerator unit18amay operate to receive communications signals from a medium-voltage power line12, amplify the communications signals and/or filter out certain types of signal noise, and then re-transmit the communications signals back on the medium-voltage power line12. In certain embodiments,wireless access point106 may operate to provide wireless access to one or more wireless devices. For example,wireless access point106 may operate to create a wireless “hot spot,” by providing wireless Internet access to one or more wireless devices. In particular embodiments,wireless access point106 may operate to allow for monitoring and/or modifying the operation ofregenerator unit18a.
• FIG. 3 illustrates an example customer-access unit18bincluded in certain embodiments of power-line communications system10. In the example shown, customer-access unit18bincludeshousing100, twomodems102,switch104,wireless access point106, andcontrol module112.
• Housing100,switch104, andwireless access point106 included in customer-access unit18bmay be the same or substantially similar to switch104 andwireless access point106 described above with regard toregenerator unit18a. For example,housing100 may operate to protect the elements of customer-access unit18band may operate to simplify the installation of customer-access unit18bby keeping the elements of customer-access unit18btogether with the appropriate internal connections. In certain embodiments,housing100 may also provide structural support for the elements of customer-access unit18band may provide electrical insulation between certain elements of customer-access unit18b. As another example, switch104 may represent any appropriate hardware and/or controlling logic for directing the flow of digital communications signals among multiple elements of customer-access unit18b. In certain embodiments, switch104 may be a router, a hub, or an Ethernet switch.
• Modems102aand102bincluded in customer-access unit18bmay be the same or substantially similar tomodems102 described above with regard toregenerator unit18a, with the exception thatmodem102bmay electrically couple to a low-voltage power line. In operation,modem102ademodulates signals received from medium-voltage power line12 and/or modulates communications signals for transmission on medium-voltage power line12; andmodem102bdemodulates signals received from a low-voltage power line and/or modulates communications signals for transmission on a low-voltage power line. Thus modems102 represent any appropriate hardware and/or controlling logic for modulating and/or demodulating communications signals.
• Control module112 operates to control the operation of certain aspects of customer-access unit18b. In certain embodiments,control module112 may serve as a firewall, a router, and/or an agent. For example,control module112 may collect and store information related to the quantity and type of communication signals received and transmitted by customer-access unit18b. As another example,control module112 may prevent particular portions of communications signals received by customer-access unit18bfrom being transmitted by customer-access unit18b. In certain embodiments,control module112 may operate to couple the elements of customer-access unit18bassociated with portions of two logical networks. In certain embodiments,control module112 may couple elements of customer-access unit18bassociated with a wide area network (WAN) and with a local area network (LAN). For example,control module112 may couplemodem102aassociated with a WAN, such as a WAN formed at least in part bycommunications network10, tomodem102bassociated with a LAN, such as a LAN associated with a customer. In certain embodiments,control module112 may serve to control and/or limit the flow of communications signals between the WAN and the LAN. In certain embodiments,control unit112 may operate to provide remote control and/or remote monitoring of certain aspects of customer-access unit18b. For example,control module112 may operate to provide remote control and/or remote monitoring through the use of simple network management protocol (SNMP) or through a terminal emulation program such as Telnet. In certain embodiments,control module112 may operate as an SNMP agent to allow a remote administrator to monitor and/or control one or more parameters related tomodems102 and/or the communications signal traffic within customer-access unit18b. In certain embodiments,control module112 may include encryption algorithms to restrict access to the control features and or to restrict access from the WAN to the LAN.
• In operation, customer-access unit18bmay receive communications signals from a medium-voltage power line12, demodulate the received communications signals, re-modulate at least a portion of the received communications signals, and transmit the re-modulated communications signal to a low-voltage power line.
• Although customer-access unit18bhas been described as receiving communications signals from medium-voltage power line12 and transmitting communications signals to a low-voltage power line, customer-access unit18bmay also receive communications signals from a low-voltage power line and transmit communications signals to medium-voltage power line12. In certain embodiments,wireless access point106 may operate to create a wireless “hot spot,” by providing wireless Internet access to one or more wireless devices. In particular embodiments,wireless access point106 may operate to allow for monitoring and/or modifying the operation of customer-access unit18b.
• FIG. 4 illustrates an example regenerator/customer-access unit18cincluded in certain embodiments of power-line communications system10. In the example shown, regenerator/customer-access unit18cincludeshousing100, twomodems102a, onemodem102b, twoswitches104, onewireless access point106, and onecontrol module112.
• Housing100,switch104,wireless access point106, andcontrol module112 included in regenerator/customer-access unit18cmay be the same or substantially similar to the same elements described above with regard toregenerator unit18aand customer-access unit18b.Modem102amay operate to electrically couple to a medium-voltage power line12 andmodem102bmay operate to electrically couple to a low-voltage power line. Incertain embodiments modem102amay be the same or substantially similar tomodem102 described with respect toregenerator unit18a. Similarly, in certain embodiments,modem102bmay be the same or substantially similar tomodem102bdescribed with respect to customer-access unit18b. Thusmodem102, included in regenerator/customer-access-unit18crepresents any appropriate hardware and/or controlling logic for modulating and/or demodulating communications signals.
• In operation, regenerator/customer-access-unit18cmay operate to regenerate communications signals on a medium-voltage power line12 and/or provide one or more customers with access tocommunications network10. In certain embodiments, regenerator/customer-access-unit18cmay function as either aregenerator unit18aor a customer-access unit18b. In a particular embodiment, regenerator/customer-access unit18cmay function as both aregenerator unit18aand a customer-access unit18b. For example, regenerator/customer-access unit18cmay receive communications signals from medium-voltage power line12, selectively communicate a portion of the received communications signals to a low-voltage power line, and selectively communicate a portion of the received communications signals to medium-voltage power line12. In certain embodiments, regenerator/customer-access unit18cmay also receive wireless signals through the use of awireless access point106. For example, wireless signals received by awireless access point106 may include instructions for monitoring and/or modifying the operation of regenerator/customer-access unit18c. As another example, wireless signals received bywireless access point106 may be transmitted to a medium-voltage power line12 by amodem102aor may be transmitted to a low-voltage power line bymodem102b. In certain embodiments,wireless access point106 may operate to create a wireless “hot spot,” by providing wireless Internet access to one or more wireless devices.
• FIG. 5 illustrates an example portion of a power-line communications system10. In the embodiment shown, power-line communications system10 includes medium-voltage phase line12,neutral line14,surge arrester16,communications device18,coupler20,conductors22 and28,ferrites24, and low-voltage communications line26. In operation, communications signals are communicated between medium-voltage phase line12 andcommunications device18 through the use ofsurge arrester16 andcoupler20. In certain embodiments,conductor22 may couplesurge arrester16 toneutral line14 and/or a ground connection.
• Conductor22 may represent any appropriate wire or cable, such as, for example, a standard #4 or #6 AWG solid copper wire. Inembodiments including conductor22, one ormore ferrites24 may be coupled toconductor22 so that the one or more ferrites substantially surround a portion ofconductor22. In operation,ferrites24 may serve as a low-pass filter preventing (or attenuating) the transmission of high-frequency signals through the portion ofconductor22 coupled to the one ormore ferrites24. Although the embodiment shown includesferrites24, in certain alternative embodiments, any suitable device may be used to provide this filtering function.
• Coupler20 is a device that couplescommunications device18 to surgearrester16. In certain embodiments,coupler20 is electrically coupled tocommunications device18 through the use of low-voltage communications line26. In certain embodiments, low-voltage communications line26 may represent any appropriate single or multi conductor cable or wire. For example, in certain embodiments, low-voltage communications line may represent a coaxial cable, an Ethernet cable, a telephone cable, or a serial cable. In certain embodiments,conductor26 may represent two or more single or multi conductor cables and/or wires. In certain embodiments,coupler20 is coupled to surgearrester16 through a direct conductive connection withsurge arrester16. For example, in certain embodiments,coupler20 is coupled to surgearrester16 throughground post29 ifarrester16. In particular embodiments,coupler20 may include a conductive portion that may include an opening large enough to slide over theground post29 ofsurge arrester16.Coupler20 may be positioned directly adjacent to (or integral to)surge arrester16, directly adjacent to (or integral to)communications device18, and/or in any other appropriate position with respect tocommunications device18 andsurge arrester16.
• In certain embodiments,coupler20 may provide an impedance match between medium-voltage phase line12 (and/or surge arrester16) and conductor26 (and/or communications device18). For example, in certain embodiments,coupler20 may include one or more capacitors and one or more impedance transformers to provide this impedance matching function. Further description of embodiments ofcoupler20 including one or more capacitors and one or more impedance transformers is provided below in relation toFIG. 7. Although, certain embodiments ofcoupler20 are described herein as including one or more capacitors and one or more impedance transformers, in other embodiments coupler20 may include other appropriate components and/or techniques to provide this impedance matching function.
• In certain embodiments, coupler20 (or variations thereof, such ascoupler120 identified below) may provide a means for bypassing an explosive disconnect device, which may improve the coupling efficiency. Embodiments providing such bypass means are described further below in relation toFIGS. 9-15.
• FIG. 6 illustrates a circuit diagram of an example portion of power-line communications system10. In the embodiment shown, power-line communications system10 includes medium-voltage phase line12,surge arrester16,communications device18, and acoupler20.Surge arrester16 is coupled tocommunications device18 through the use ofcoupler20. In the embodiment shown,coupler20 is connected tocommunications device18 through the use of low-voltage communications line26, which includesconductors34aand34b.
• In the embodiment shown,coupler20 includes animpedance transformer30 and acapacitor32. As shown,conductor34ais coupled to the non-common low-impedance winding ofimpedance transformer30, whileconductor34bis coupled to the common winding ofimpedance transformer30 on both the primary and secondary. In certain embodiments,conductor34bmay also be coupled toneutral line14 and/or a ground connection. As shown, in certain embodiments, the non-common common winding of the high-impedance side ofimpedance transformer30 is coupled to acapacitor32, which is coupled to surgearrester16.
• In certain embodiments, medium-voltage phase line12 (and/or surge arrester16) may have an impedance in the range from 350-450 ohms and conductor26 (and/or communications device18) may have an impedance in the range from 50-75 ohms. In certain embodiments, to match impedances,impedance transformer30 may represent a transformer with a step-up ratio in the range from approximately 5:1 to 9:1. For example, in a particular embodiment,impedance transformer30 may represent a transformer with a step-up ratio of approximately 8:1, such as for example a Mini Circuits T8-1 transformer. In certain embodiments,capacitor32 may have a capacitance in the range of 0.01 to 0.1 microfarads andcapacitor32 may have a working capacity greater than 300 volts. For example, in a particular embodiment,capacitor32 may represent a 0.047 microfarad 600 volt coupling capacitor. Although example embodiments includingimpedance transformer30 andcapacitor32 have been described as having certain characteristics or ranges of characteristics, any appropriate components may be used to match (or improve the matching of) impedances within power-line communications system10 without departing from the spirit and scope of the present invention. In certain embodiments, for example, power-line communications system10 and/orcoupler20 may include different connection topologies and/or different types ofimpedance transformers30. In a particular embodiment, certain functions of the present invention may be accomplished using a transmission line transformer.
• FIG. 7 illustrates a component diagram of an example configuration ofcoupler20, according to a particular embodiment. As shown,coupler20 includesimpedance transformer30,capacitor32,base40, andconnectors42 and44.Impedance transformer30 andcapacitor32 operate as described above in relation toFIG. 6.
• Base40 represents any appropriate structure for supporting the components ofcoupler20. For example,base40 may represent a housing that physically surrounds one or more components ofcoupler20. As another example,base40 may represent a substrate upon which certain components may be positioned, such as a 1″×2″ printed circuit board. In particular embodiments,base40 may include one or more protective coverings. For example,base40 may include coverings adapted to provide weather and/or UV protection for certain components ofcoupler20. In a particular embodiment,base40 may represent a printed circuit board coated with a first coat of Humiseal 1A20 Polyurethane and a second coat of Humiseal 1C49 Silicone.
• Connector42 represents a conductive connector adapted to electrically connectcoupler20 tocommunications device18. In certain embodiments,connector42 may connectcoupler20 tocommunications device18 through low-voltage communications line26. In a particular embodiment, low-voltage communications line26 may represent a coaxial cable andconnector42 may represent a coaxial connector, such as a BNC connector or an F-connector.
• Connector44 represents a conductive connector adapted to electrically connectcoupler20 to surgearrester16. In certain embodiments,connector44 may connectcoupler20 to surgearrester16 through the use of one or more conductive cables or wires. In other embodiments,connector44 may connectcoupler20 to surgearrester16 throughground post29 onsurge arrester16. For example, in the illustrated embodiment,connector44 may represent a conductive material with an opening adapted to acceptground post29 ofsurge arrester16. For example,connector44 may represent a metallic disk (or cylinder) with a thru-hole that is approximately 0.375-0.400 inches in diameter. In the embodiment shown,connector44 is positioned integral tobase40 such that, in operation,base40 withconnector44 may slide over ground post29 ofsurge arrester16 to establish a conductive contact withground post29 and/or a retaining nut threaded ontoground post29.
• In embodiments includingimpedance transformer30 and/orcapacitor32,impedance transformer30 and/orcapacitor32 may be electrically connected in series betweenconnector42 andconnector44. In certain embodiments,base40 may provide the electrical coupling between components ofcoupler20. For example, in embodiments whereinbase40 represents a printed circuit board, integrated conductors ofbase40 may provide the electrical coupling.
• FIG. 8 illustrates a portion of an example power-line communications system10 including anexample surge arrester16, anexample disconnect device50, an exampleparallel bypass60 includingbypass capacitor62, and anexample coupler20, according to a particular embodiment. As shown, in certain embodiments,parallel bypass60 may conductively connect betweensurge arrester16 anddisconnect device50. In the embodiment shown,parallel bypass60 connects to coupler20, which, in turn, couples to both low-voltage communications line26 anddisconnect device50. As discussed further in relation toFIGS. 9 and 10, in certain embodiments, variations of coupler20 (such as coupler120) may includebypass capacitor62. In operation,capacitor62 may provide a low-impedance bypass arounddisconnect device50 for certain frequencies. In certain embodiments, one or more ofsurge arrester16,disconnect device50,parallel bypass60,bypass capacitor62 andcoupler20 may be included within a single component. Similarly, one or more of the functions provided bysurge arrester16,disconnect device50,parallel bypass60,bypass capacitor62, orcoupler20 may be served by multiple components.
• FIG. 9 illustrates a circuit diagram of an example medium-voltage powerline disconnect device50. As shown,disconnect device50 may function as aresistor52 in parallel with anair gap54. In operation, a high-voltage spike may result in a spark acrossair gap54, which may ignite a gun-powder charge to disconnectsurge arrester16 fromconductor22.Resistor52 may represent any component or group of components that operate to provide a resistance to an electrical current. Forexample resistor52 may represent a grading resistor. In certain embodiments, due to the presence ofresistor52,disconnect device50 may limit the transmission efficiency for communications signals between medium-voltage power lines andcommunications device16.
• FIG. 10 illustrates a circuit diagram of an example medium-voltage powerline disconnect device50 with an exampleparallel bypass60 includingbypass capacitor62, according to a particular embodiment. In certain embodiments, to improve the transmission efficiency for the communications signal coupling, aparallel bypass60 may be utilized.Parallel bypass60 may broadly represent a circuit path in parallel withdisconnect device50. For example,parallel bypass60 may be a copper wire conductively coupled betweensurge arrester16 anddisconnect device50. In certain embodiments, as shown inFIG. 10,parallel bypass60 may includecapacitor62.Capacitor62 may broadly represent one or more components operable to provide capacitance forparallel bypass60. For example, in a particular embodiment,capacitor62 may represent a ceramic disk capacitor, such as a 1000 picofarad, 3 kV capacitor.
• FIG. 11 illustrates a circuit diagram of a portion of an example power-line communications system10, including anexample disconnect device50 and an exampleparallel bypass60 includingbypass capacitor62, according to a particular embodiment. In the embodiment shown,communications device18 is connected toneutral line14, throughconductor28, and tocoupler20. In the embodiment shown,coupler20 is connected to surgearrester16 throughdisconnect device50 in parallel withparallel bypass60.Coupler20 may or may not include components providing an impedance matching function.
• FIG. 12 illustrates a component diagram of an example configuration ofcoupler120, a variation ofcoupler20 including abypass capacitor62. As shown, in certain embodiments,coupler120amay includebase40,bypass capacitor62, andconnectors42,44, and90.Connector90 may broadly represent a connector for electrically couplingparallel bypass60 to coupler120a. Thus,connector90 may represent any appropriate hardware for electrically coupling toparallel bypass60. In the embodiment shown,capacitor62 is connected in series betweenconnector90 andconnector44.
• FIG. 13 illustrates a component diagram of an example configuration ofcoupler120, a variation ofcoupler20 including abypass capacitor62. As shown, in certain embodiments,coupler120bincludes both abypass capacitor62 and impedance matching components. In the embodiment shown,coupler120bincludesbypass capacitor62, connected in series withconnector90, andimpedance transformer30 andcapacitor32, connected in series withconnector42. In this embodiment,coupler120bmay operate to couplecommunications device18 to medium-voltage power line12 with improved efficiency by bypassingdisconnect device50 and by matching impedances between medium-voltage power line12 andcommunications device18.
• FIG. 14 illustrates a portion of an example power-line communications system10 including anexample surge arrester16, anexample disconnect device50, an exampleparallel bypass60, and anexample coupler120, according to a particular embodiment. As shown, in certain embodiments,parallel bypass60 may conductively connect betweensurge arrester16 anddisconnect device50. In the embodiment shown,parallel bypass60 connects to coupler20, which, in turn, couples to both low-voltage communications line26 anddisconnect device50. In the embodiment shown inFIG. 14, unlike the embodiment shown inFIG. 8,parallel bypass60 does not include bypass capacitor. Rather, in this embodiment, thebypass capacitor62, if any, is included as a component ofcoupler120.
• FIG. 15 illustrates a circuit diagram of a portion of an example power-line communications system10, including anexample disconnect device50 and an exampleparallel bypass60, according to a particular embodiment. In the embodiment shown,communications device18 is connected toneutral line14, throughconductor28, and tocoupler120. In the embodiment shown,coupler120 is connected to surgearrester16 throughdisconnect device50 in parallel withparallel bypass60. In the embodiment shown inFIG. 15, unlike the embodiment shown inFIG. 11,parallel bypass60 does not include bypass capacitor. Rather, in this embodiment, thebypass capacitor62, if any, is included as a component ofcoupler120. In certain embodiments, although not necessary,coupler120 may include both abypass capacitor62 and impedance matching components.
• Although the present invention has been described with several embodiments, a plenitude of changes, substitutions, variations, alterations, and modifications may be suggested to one skilled in the art, and it is intended that the invention encompass all such changes, substitutions, variations, alterations, and modifications as fall within the spirit and scope of the appended claims.

Claims (26)

1. A system for communicating signals over a medium-voltage power line, the system comprising:

a communications device comprising at least one modem; and

a coupler comprising:

a coaxial connector coupled to the communications device;

an impedance transformer electrically coupled to the coaxial connector, the impedance transformer having a step-up ratio of approximately 8: 1;

a capacitor electrically coupled to the impedance transformer, the capacitor having a capacitance of approximately 0.05 microfarads;

a conductive metallic disk electrically coupled to the capacitor, the conductive metallic disk defining a substantially circular opening adapted to accept a ground post from a lightning arrester; and

a circuit board, wherein the connector, the capacitor, the impedance transformer, and the conductive disk are coupled to the circuit board.

2. A system for communicating signals on a medium-voltage power line, the system comprising:

a communications device; and

a coupler comprising:

a first connector adapted to couple to the communications device;

an impedance transformer;

a capacitor; and

a second connector defining an opening adapted to accept a ground post from a surge arrester.

3. The system ofclaim 2, wherein the first connector is adapted to couple to a coaxial cable having an impedance of approximately 50-75 ohms.

4. The system ofclaim 2, wherein the impedance transformer provides a step-up ratio in the range from 5:1 to 9:1.

5. The system ofclaim 2, wherein the capacitor provides a capacitance in the range from 0.01 to 0.1 microfarads.

6. The system ofclaim 2, wherein the second connector comprises a metallic disk.

7. The system ofclaim 2, wherein the opening has a diameter in the range from 0.25 to 0.75 inches.

8. The system ofclaim 2, wherein:

the coupler further comprises a circuit board; and

the first connector, the capacitor, the impedance transformer, and the second connector are coupled to the circuit board.

9. A device for coupling communications signals to a medium-voltage power line, the device comprising:

a first connector adapted to couple to a low-voltage communications line;

an impedance transformer;

a capacitor; and

a second connector adapted to couple to a surge arrester.

10. The device ofclaim 9, wherein the low-voltage communications line comprises a coaxial cable having an impedance of approximately 50-75 ohms.

11. The device ofclaim 9, wherein the impedance transformer provides a step-up ratio in the range from 5:1 to 9:1.

12. The device ofclaim 9, wherein the capacitor provides a capacitance in the range from 0.01 to 0.1 microfarads.

13. The system ofclaim 9, wherein the second connector comprises a metallic disk which defines a substantially circular opening with a diameter in the range from 0.25 to 0.75 inches.

14. The device ofclaim 9, further comprising a circuit board; wherein the first connector, the capacitor, the impedance transformer, and the second connector are coupled to the circuit board.

15. A device for coupling communications signals to a medium-voltage power line, the device comprising:

a base;

one or more electrical components;

a first connector adapted to couple to a low-voltage communications line; and

a second connector adapted to conductively couple to a surge arrester, the second connector defining a substantially circular opening adapted to accept a ground post from the surge arrester;

wherein the one or more electrical components, the first connector, and the second connector are physically coupled to the base.

16. The device ofclaim 15, wherein the base comprises a circuit board.

17. The device ofclaim 16, further comprising a protective coating covering at least a portion of the circuit board, the protective coating adapted to seal the at least a portion of the circuit board against moisture.

18. The device ofclaim 15, wherein the one or more electrical components are operable to provide impedance matching.

19. The device ofclaim 15, wherein the second connector comprises a metallic disk.

20. The device ofclaim 15, wherein the substantially circular opening has a diameter in the range from 0.2 inches to 0.8 inches.

21. The device ofclaim 15, wherein the substantially circular opening has a diameter of 0.4 inches.

22. A device for coupling communications signals to a medium-voltage power line, the device comprising:

a first connector adapted to couple to a low-voltage communications line;

a second connector adapted to couple to a surge arrester; and

one or more components operable to substantially match the impedances between the surge arrester and the low-voltage communications line.

23. The device ofclaim 22, wherein the one or more components comprise an impedance transformer having a step-up ratio in the range from 5:1 to 9:1 in series with a capacitor having a capacitance in the range from 0.01 to 0.1 micro farads.

24. The device ofclaim 22, wherein the low-voltage communications line comprises a coaxial cable.

25. A method for coupling communications signals to a medium-voltage power line, the method comprising:

transmitting a communications signal:

from a signal regenerator;

through a low-voltage communications line;

through one or more components operable to increase impedance by a ratio of between 5:1 and 9:1;

through a surge arrester; and

to a medium-voltage power line.

26. A device for coupling communications signals to a medium-voltage power line, the device comprising:

a means for coupling to a low-voltage communications line;

a means for coupling to a surge arrester; and

a means for substantially matching the impedances between the surge arrester and the low-voltage communications line.

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